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MHT CET202615 April 2026Evening ShiftPhysicsCurrent ElectricityActual

A potentiometer wire is 4m long and potential difference of 2V is maintained between the ends. The e.m.f. of the cell which balances against a length of 80 cm of the potentiometer wire is

Options

  1. A0.25 V
  2. B0.30 V
  3. C0.40 V
  4. D0.80 V

Correct answer

C. 0.40 V

Step-by-step solution

Length of the potentiometer wire, L = 4 m Potential difference across the wire, V = 2 V Potential gradient of the wire, k = V L = 2 4 = 0.5 V/m Balancing length for the cell, l = 80 cm = 0.8 m The e.m.f. of the cell is given by E = k l E = 0.5 0.8 = 0.40 V Answer: 0.40 V

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